[net.columbia] Composite SRBs scrapped? and Tidbits about shuttle climb attitude

fisher@star.DEC (Burns Fisher ZKO1-1/D42 DTN 381-1466) (03/13/86)

From Aviation Week, March 10, 1986:

Senior NASA engineers said that, in light of the accident and
concerns raised even before the accident, it is unlikely that
they will approve use of (composite case SRBs) because of serious
flight safety concerns involved with using such materials.

A decision not to use the lighter composite cases would seriously
affect the US Air Force's plans to launch a heavy (spy satellite).
Without the lightweight cases, Vandenberg shuttle payloads for missions
to polar orbits would be reduced to about 27,000 pounds--5000 lb. below
that needed for the new recon spacecraft that represents one of the 
shuttle's most important military payloads.

--->Use of a "heads up" launch technique from Vandenbert, instead of the
inverted flight attitude used for climbout from Kenedy, is under 
consideration as a possible solution to the payload problem.  The
shuttle would be launched so that the crew rides upright through about
Mach 2, instead of rolling inverted shortly after liftoff.

Using this technique could recover about 4,000 lb. of the payload shortfall.
But it raises flight technique, abort and other issues--including the need
to increase the initial thrust of the steel case solid boosters
that would be used in place of the composite boosters.

<End of quote from Aviation Week...editing in parens is mine>

Can anyone speculate on why flying upside down causes a loss of 4000 lb
of payload capacity?  Perhaps lift from the wings pushing the craft down?

Burns

...decwrl!rhea!star!fisher